Purchase potentiometers need to understand these technical parameters

Purchasing a potentiometer is not only about purchasing a potentiometer by knowing the model of the potentiometer. In addition to the appearance of the potentiometer, we should also understand the technical parameters of the junction potentiometer in order to choose the correct potentiometer to apply to the product. The main thing to understand is Those who are not clear about the following can pay attention to them.

The main parameters of the potentiometer include nominal resistance, sliding noise, rated power, zero resistance, resolution, wear resistance, resistance change characteristics and temperature coefficient.

(1) Nominal resistance, zero resistance and rated power

The nominal resistance value is the resistance value marked on the potentiometer, that is, the resistance value between the two fixed ends of the potentiometer; the zero resistance refers to the minimum resistance value of the potentiometer, that is, the smallest resistance value between the moving end and any certain end; The rated power of the device refers to the maximum power that can be consumed by long-term continuous load at the specified rated temperature when the atmospheric pressure is 87~107 kPa in the AC and DC circuits.

(2) Resistance change characteristics of the potentiometer

The resistance change characteristic of the potentiometer refers to the relationship of the resistance value of the potentiometer with the change of the length of the movable contact or the angle of the rotating shaft, that is, the resistance output function characteristic. There are 3 commonly used:

1) Exponential (Z type)

2) Logarithmic formula (D type)

3) Linear type (X type)

(3) Resolution of the potentiometer

The resolution of the potentiometer is also called the resolution of the potentiometer. For the wire-wound potentiometer, the ratio of the output voltage change of the potentiometer to the output voltage is the resolution when the movable contact moves one circle. As for the linear winding potentiometer, its theoretical resolution is the reciprocal of the total number of winding turns and expressed as a percentage. The more the total number of turns of the potentiometer, the higher the resolution.

(4) Dynamic noise of the potentiometer

The dynamic noise of the potentiometer refers to the electrical noise generated when the potentiometer is under the action of an applied voltage and its moving contact point slides on the resistor. Dynamic noise is the main parameter of sliding noise, and its magnitude is related to the speed of the shaft, the contact resistance between the contact point and the resistor, the uneven change of the resistivity of the resistor, the number of moving contact points and the magnitude of the applied voltage.